1. Field of the Invention
The present invention relates to a valve actuating cam shaft driving system for an internal combustion engine in which a power output gear integrally formed on a crankshaft is operatively connected to a speed change gearing mechanism via an intermediate gear on an intermediate shaft and further the crankshaft is operatively connected to a valve actuating cam shaft adapted to actuate suction and exhaust valves.
2. Description of the Prior Art
It has been hitherto known that a conventional valve actuating cam shaft driving system often suffers from a few drawbacks during a high speed operation of an engine, such as lowering of the operational stability of a valve actuation system, stoppage of increase in engine output, minor mechanical trouble in the valve actuating system or the like. To obviate these drawbacks it has been proposed that the valve actuating system is provided with a shock absorbing device incorporated therein. However, the proposed shock absorbing device had to be constructed in a large size in order to ensure its sufficient shock absorbing function. Obviously, it is very difficult to employ the proposed large shock absorbing device because such device requires a wide space for mounting.